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dc.contributor.authorMorgan, Garry T.
dc.contributor.authorJones, Peter L.
dc.contributor.authorBellini, Michel
dc.date2022-08-11T08:10:14.000
dc.date.accessioned2022-08-23T17:00:50Z
dc.date.available2022-08-23T17:00:50Z
dc.date.issued2012-12-01
dc.date.submitted2014-12-04
dc.identifier.citationChromosome Res. 2012 Dec;20(8):925-42. doi: 10.1007/s10577-012-9324-x. <a href="http://dx.doi.org/10.1007/s10577-012-9324-x">Link to article on publisher's site</a>
dc.identifier.issn0967-3849 (Linking)
dc.identifier.doi10.1007/s10577-012-9324-x
dc.identifier.pmid23149574
dc.identifier.urihttp://hdl.handle.net/20.500.14038/43879
dc.description<p>At the time of publication, Peter Jones was not yet affiliated with the University of Massachusetts Medical School.</p>
dc.description.abstractWe have investigated the association of DNA methylation and proteins interpreting methylation state with the distinctive closed and open chromatin structural domains that are directly observable in the lampbrush chromosomes (LBCs) of amphibian oocytes. To establish the distribution in LBCs of MeCP2, one of the key proteins binding 5-methylcytosine-modified DNA (5mC), we expressed HA-tagged MeCP2 constructs in Xenopus laevis oocytes. Full-length MeCP2 was predominantly targeted to the closed, transcriptionally inactive chromomere domains in a pattern proportional to chromomeric DNA density and consistent with a global role in determining chromatin state. A minor fraction of HA-MeCP2 was also found to associate with a distinctive structural domain, namely a short region at the bases of some of the extended lateral loops. Expression in oocytes of deleted constructs and of point mutants derived from Rett syndrome patients demonstrated that the association of MeCP2 with LBCs was determined by its 5mC-binding domain. We also examined more directly the distribution of 5mC by immunostaining Xenopus and axolotl LBCs and confirmed the pattern suggested by MeCP2 targeting of intense staining of the chromomeres and of some loop bases. In addition, we found in the longer loops of axolotl LBCs that short interstitial regions could also be clearly stained for 5mC. These 5mC regions corresponded precisely to unusual segments of active transcription units from which RNA polymerase II (pol II) and nascent transcripts were simultaneously absent. We also examined by immunostaining the distribution in lampbrush chromatin of the oxidized 5mC derivative, 5-hydroxymethylcytosine (5hmC). Although in general, the pattern resembled that obtained for 5mC, one antibody against 5hmC produced intense staining of restricted chromosomal foci. These foci corresponded to a third type of lampbrush chromatin domain, the transcriptionally active but less extended structures formed by clusters of genes transcribed by pol III. This raises the possibility that 5hmC may play a role in establishing the distinctive patterns of gene repression and activation that characterize specific pol III-transcribed gene families in amphibian genomes.
dc.language.isoen_US
dc.relation<a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&list_uids=23149574&dopt=Abstract">Link to Article in PubMed</a>
dc.rights<p>Copyright © The Author(s) 2012. This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.</p>
dc.subject5-Methylcytosine; Animals; Chromatin; Chromosomes; Cytosine; DNA; DNA Methylation; Gene Expression Regulation; Humans; Immunoblotting; Methyl-CpG-Binding Protein 2; Mutation; Oocytes; RNA Polymerase II; Sequence Analysis, DNA; Transcription, Genetic; Xenopus laevis
dc.subjectLampbrush chromosomes
dc.subjectMethylation
dc.subject5-hydroxymethylcytosine
dc.subjectOocyte
dc.subjectTranscription unit
dc.subjectCell Biology
dc.subjectDevelopmental Biology
dc.subjectMolecular Biology
dc.subjectMolecular Genetics
dc.subjectMusculoskeletal Diseases
dc.subjectNervous System Diseases
dc.titleAssociation of modified cytosines and the methylated DNA-binding protein MeCP2 with distinctive structural domains of lampbrush chromatin
dc.typeJournal Article
dc.source.journaltitleChromosome research : an international journal on the molecular, supramolecular and evolutionary aspects of chromosome biology
dc.source.volume20
dc.source.issue8
dc.identifier.legacyfulltexthttps://escholarship.umassmed.edu/cgi/viewcontent.cgi?article=1018&amp;context=peterjones&amp;unstamped=1
dc.identifier.legacycoverpagehttps://escholarship.umassmed.edu/peterjones/19
dc.legacy.embargo2014-12-11T00:00:00-08:00
dc.identifier.contextkey6422503
refterms.dateFOA2022-08-23T17:00:51Z
html.description.abstract<p>We have investigated the association of DNA methylation and proteins interpreting methylation state with the distinctive closed and open chromatin structural domains that are directly observable in the lampbrush chromosomes (LBCs) of amphibian oocytes. To establish the distribution in LBCs of MeCP2, one of the key proteins binding 5-methylcytosine-modified DNA (5mC), we expressed HA-tagged MeCP2 constructs in Xenopus laevis oocytes. Full-length MeCP2 was predominantly targeted to the closed, transcriptionally inactive chromomere domains in a pattern proportional to chromomeric DNA density and consistent with a global role in determining chromatin state. A minor fraction of HA-MeCP2 was also found to associate with a distinctive structural domain, namely a short region at the bases of some of the extended lateral loops. Expression in oocytes of deleted constructs and of point mutants derived from Rett syndrome patients demonstrated that the association of MeCP2 with LBCs was determined by its 5mC-binding domain. We also examined more directly the distribution of 5mC by immunostaining Xenopus and axolotl LBCs and confirmed the pattern suggested by MeCP2 targeting of intense staining of the chromomeres and of some loop bases. In addition, we found in the longer loops of axolotl LBCs that short interstitial regions could also be clearly stained for 5mC. These 5mC regions corresponded precisely to unusual segments of active transcription units from which RNA polymerase II (pol II) and nascent transcripts were simultaneously absent. We also examined by immunostaining the distribution in lampbrush chromatin of the oxidized 5mC derivative, 5-hydroxymethylcytosine (5hmC). Although in general, the pattern resembled that obtained for 5mC, one antibody against 5hmC produced intense staining of restricted chromosomal foci. These foci corresponded to a third type of lampbrush chromatin domain, the transcriptionally active but less extended structures formed by clusters of genes transcribed by pol III. This raises the possibility that 5hmC may play a role in establishing the distinctive patterns of gene repression and activation that characterize specific pol III-transcribed gene families in amphibian genomes.</p>
dc.identifier.submissionpathpeterjones/19
dc.contributor.departmentDepartment of Cell and Developmental Biology
dc.source.pages925-42


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